We previously demonstrated that GHCer shed from tumor cells suppresses the activation of T and B lymphocytes.[1] To evaluate the effects of GHCer on Treg differentiation, human CD4+ T cells were incubated with TGF‐β (5 ng ml−1), IL‐2 (100 U ml−1), anti‐CD3 (1 μg ml−1), and anti‐CD28 (5 μg ml−1) antibodies for 6 days, along with 30 μM of either globosides, GHCer, SSEA3Cer (SSEA3 cermide), SSEA4Cer (SSEA4 cermide), or PBS as a control. This evidence concerns the gene CD28 and neoplasm.